If there is, or was, life on Mars, how did it get there? We have some ideas.

Long Live Curiosity, the mobile Mars Scientific Laboratory! I think it is highly unlikely, virtually impossible, that Mars does not contain the chemical elements that Curiosity is looking for, the building blocks of life, even if buried beyond the reach of Curiosity’s instrumentation.

If hot springs, hydrothermal vents, or subsurface water are found, the chances of finding life take a huge bound farther into the realm of the likely, rather than the more possible. Then we get into the big question of whether Martian extremophiles could, or can, survive the radiation and temperature differentials, and shortage of water, of the red planet.

If there is life on Mars, there is the big and contentious question of how it got there. Did it start during the formation of the solar system, when the planet was being formed and the atmosphere was turbulent in all respects – chaotic and creative. In 1953, American chemists Stanley Miller and Harold Urey set out to prove the several similar theories with an experiment that replicated, in the lab, the conditions thought to exist in Earth’s early history, hoping to prove that they could produce amino acids from ammonia and methane.

With an array of flasks they heated water until it became water vapor, allowed it to mix with methane, ammonia, and hydrogen, and let the mixture move into a second flask that contained electrodes, which were fired to create a minute lightning flash. The water was then allowed to condense and return to its liquid state. In two weeks of repeating this cycle, the brew was found to contain more than 20 different kinds of amino acids. Eureka!

Amino acids are the building blocks of proteins required to support life. In 2002 a trio of Princeton scientists, using computer simulation, analyzed the constituents of “old” genes that have been extant for as many years ago as we can measure. Their results made them confident enough to propose that the amino acid composition of proteins in the old genes was very close to those that occurred in the development of the genetic code. If on Earth, who not on Mars?

About 100 chunks of Martian rock – meteorites – have been found on Earth, but they not contain the chemical cocktails that would encourage the emergence of life’s precursors. (A few contain vaguely fossil-like shapes, but their biological origin is mostly discounted.)

Meteorites apart, the building blocks of life have already been found on extraterrestrial objects – most convincingly as a result of NASA’s Stardust Mission, designed to bring back samples from the tail of a comet. Among the materials found was the amino acid glycine

I was lucky to be present at the Royal Institution when Fred Hoyle held forth on his belief in panspermia, a competing idea that holds that life forms such as pollen and even bacteria can survive the environments of space and settle down on, for example, Earth or Mars. I remember Hoyle’s great sense of conviction that this idea, of which its basic elements were first proposed by Anaxagorus in ancient Greece, was alive and blooming all over the cosmos, or at least the solar system. The idea is seductive – at some ancient time a planet harboring life is struck by another object and part of its crust, containing viable spores or pollen, is thrust with huge force out of the planet’s gravitation field and into orbit, or a cloud of orbits. Hoyle hoped that the more advanced organisms would be found embedded in the dirty ice of comets.

At this point I favor the in-situ development of life’s precursors to the magical arrival of viable structures from the sky. (Will humanity survived by spurting clouds of ready-packed fertilized ova into the unready skies?) Others must be doubting too, for the original idea seems have lost ground despite the enthusiasm of Chandra Wickramasinghe, who became Hoyle’s colleague with the rebirth of panspermia in the 1970s and has carried the torch since his mentor’s death. Now we have “Cosmic Ancestry,” in capital letters, which is derived from panspermia and uses its name, but is more definitive in its theories of what happened and when. Its motto is “Life comes from space because life comes from life.” Its supporters claim there was life before the Big Bang, and it has been on Earth for more than 3 billion years, and something put it here; science cannot answer what existed before the Big Bang, or what caused life to exist in the first place (Hoyle favored some sort of higher intelligence).

Yes Virginia, there is another universe, and maybe a pan-universal Big Brother as well..

Seriously these are wonderfully fascinating subjects and one can only join in with NASA, ESA, and their supporters, in their enthusiasm for the Mars Scientific Laboratory. But when I hear NASA’s dreams for a manned mission to Mars, flying to the red planet with six astronauts for six months and returning after eight months, the doubt-generating areas of my brain begin to light up. Sure, I hope something of the sort succeeds, as an international project, someday. But we don’t have the technology to do it now, and we don’t know how well an astronaut team can work – and survive – in that hostile, radiation-rich atmosphere. And we don't know when we'll have the money.